The present invention relates to a casing brake assembly for applying a frictional force to a tubular or bag-shaped packaging casing being temporarily arranged on a filling tube of an apparatus for filling and closing the tubular or bag-shaped packaging casing, like a clipping machine. The casing brake assembly is provided for limiting the movement of the packaging casing at least while being filled during a filling process. The filling tube has a circular cross-section and a longitudinal filling tube axis.
In practice, it is known that, for example in the production of sausage-shaped products, like sausages, flowable filling material is fed by a filling machine through a filling tube of a clipping machine in a feeding direction into a tubular or bag-shaped packaging casing, which is stored on the filling tube and which is closed at its front end, i.e. the end pointing in the feeding direction of the filling material, by a closure means, like a closure clip. The tubular packaging casing is pulled-off the filling tube while being filled due to a pulling force caused by the feeding pressure of the filling material discharged from the filling tube. At least during the filling process, a casing brake applies a frictional force to the tubular packaging casing that is being pulled-off from the filling tube, in order to control the pull-off speed and to ensure an at least approximately constant filling degree. After a predetermined volume of filling material has been filled into said tubular packaging casing, a plait-like portion of the tubular packaging casing is formed by a displacer arrangement. Known displacer arrangements generally comprise a first and a second displacer unit which can each be formed by a pair of reversibly moveable displacer elements. The clipping machine then places and closes at least one closure clip at the plait-like portion by respective closing tools, thus forming the rear end of the sausage shaped product, i.e. the end pointing against the feeding direction and the front end of the successive sausage-shaped product to be produced, respectively. The closing tools are reversibly movable towards the plait-like portion.
In EP patent application 1 428 437, a clipping machine with a fixedly arranged filling tube and a casing brake assembly is disclosed. The casing brake assembly is attached to a frame element of the clipping machine. The casing brake itself is a closed circular construction and has a closed circular lip, which surrounds the filling tube completely. A fork-shaped holding element including two rake struts, accommodates and supports the casing brake, especially in its operation position on the filling tube. For removing the casing brake from the clipping machine, the casing brake assembly has to be moved along the filling tube in the feeding direction until the casing brake is completely shifted off the filling tube. Thereafter, the casing brake may be removed from the fork-shaped holder in a direction perpendicular to the longitudinal axis of the filling tube.
A further known casing brake assembly for a fixedly arranged filling tube is disclosed in EP patent application 1 987 719. The casing brake assembly includes two brake rings. An inner brake ring is fixedly and coaxially to the filling tube axis mounted on the filling tube and comprises a brake surface arranged at its outer circumference. An outer brake ring is provided for coaxially surrounding the inner brake ring on the filling tube. The outer brake ring comprises a circular lip, which is engaged with the packaging casing material that is on the brake surface of the inner brake ring for applying a frictional force to the tubular packaging casing material guided between the two brake rings. For adjusting the brake force applied to the packaging casing, the outer brake ring can be shifted along the filling tube relatively to the inner brake ring. For removing at least the outer brake ring from the filling tube, e.g. in order to refill tubular packaging casing material onto the filling tube, the outer brake ring has to be shifted in the feeding direction along the filling tube axis until it is moved off the filling tube.
For all of these known assemblies, additional space has to be provided in the region of the discharge end of the filling tube, i.e. the end of the filling tube that is facing in feeding direction, in order to provide the required space for the casing brake assembly or parts thereof, respectively, when being moved off the filling tube. In order to provide the required space, the displacer arrangement and/or the clipping machine which are positioned downstream the filling tube, have to be configured for being reversibly moved in the feeding direction. This technical requirement demands an additional effort in their construction and additional space at the installation site.
Thus, it is an object of the present invention to provide a casing brake assembly, which overcomes the above mentioned drawbacks, and which allows a simplified and compact construction of a clipping machine.